Supported transition metal composition

ABSTRACT

A supported transition metal composition is obtained by suspending a support material in an inert liquid medium, spraying the suspension, collecting a solid material and contacting the sprayed solid with a transition metal compound. The support material may be a metal halide such as magnesium chloride or an inorganic oxide such as silica or alumina. In addition to being contacted with the transition metal compound, the support material may be contacted either before or after the spraying step with other reagents such as organo metallic compounds, halogen compounds, or Lewis Base compounds. The product obtained after contacting with the transition metal compound may be used as a component of a polymerization catalyst system to polymerize an unsaturated monomer such as ethylene or propylene.

The present invention relates to processes for producing a supportedtransition metal composition, and also to the use of the supportedtransition metal compositions as a component of a polymerisationcatalyst system and is further concerned with the polymerisation ofunsaturated monomers, particularly olefin monomers such as ethylene andpropylene, using such catalyst systems.

Since the original discovery of the so-called "Ziegler" polymerisationcatalyst systems for polymerising olefin monomers such as ethylene andpropylene, there have been considerable advances in the polymerisationof olefin monomers using these catalyst systems. Many of the advanceshave been related to developments in the catalyst systems and, inparticular, to the use of catalyst systems in which the effectivecatalyst component is present on a support material. Using such catalystsystems, a high yield of polymer may be obtained relative to thetransition metal component which is present in the polymerisationcatalyst. However, the catalyst system obtained may be such that thepolymer product is obtained as irregular particles having a wideparticle size distribution. Such polymer particles will generally have alow packing density and in order to achieve maximum yield in apolymerisation vessel of a given size it is desirable that the polymerformed should have a high packing density. Accordingly, it is desirableto improve the form of the polymer obtained and, since this isinfluenced by the form of the catalyst particles, it is desirable toimprove the form of the catalyst particles.

According to the present invention there is provided a process for theproduction of a supported transition metal composition wherein a solidsupport material is suspended in a liquid hydrocarbon or halohydrocarbonmedium, the suspension is spray-dried, the spray-dried support materialis collected and thereafter subjected to a stage in which it iscontacted with at least one compound of a transition metal of Group IVA,VA, or VIA of the Periodic Table.

All references herein to the Periodic Table are to the Short PeriodicTable as set out inside the back cover of "General and InorganicChemistry" by J. R. Partington, Second Edition, published by MacMillianand Company Limited, London, 1954.

For convenience hereafter, the term "transition metal" will be used tomean a transition metal of Group IVA, VA or VIA of the Periodic Table.

The solid support material may be any support material which has beenproposed hitherto for use as a support for a transition metal compoundin a polymerisation catalyst, and in particular, it is preferred thatthe support material in an inorganic compound. Preferred supportmaterials are metal halides, metal oxides or mixtures or reactionproducts of two or more such metal compounds. The term metal is usedherein to include silicon. If the support material is a metal halide itis preferably a halide of a divalent metal, for example a magnesiumhalide. A metal halide support material is preferably chloride, inparticular, manganese chloride or especially magnesium chloride.Suitable metal oxides which may be used include the oxides of the metalsof Groups I to IV of the Periodic Table. Oxides which may be used assilica, alumina, magnesia and mixtures or reaction products of two ormore thereof, for example, magnesium trisilicate which may berepresented as (MgO)₂ (SiO₂)₃ xH₂ O (where x is a positive number).

The liquid medium in which the support material is suspended ispreferably one which does not have a harmful effect on the supportedtransition metal composition which is obtained by contacting thespray-dried solid with the transition metal compound. Thus, a wide rangeof liquids may be used as the liquid medium provided that any residualquantities of the liquid which remain in the spray-dried supportmaterial are insufficient to have a harmful effect on the supportedtransition metal composition when this is used as a component of apolymerisation catalyst. In general, it is preferred that the liquidmedium is an inert liquid. Thus, the liquid medium is preferably analiphatic hydrocarbon such as hexane, heptane, octane, decane, dodecaneor mixtures thereof or an aromatic hydrocarbon such as benzene, tolueneor xylene or a halohydrocarbon such as cholorobenzene or1,2-dichloroethane.

The relative proportions of the support material and the liquid mediumshould be such that a mobile suspension of the support material in theliquid medium is obtained. Thus, typically it is preferred to use theliquid medium in the proportions of at least 0.5 cm³ for each gramme ofthe support material and, in particular, it is preferred to use at leastone cm³ of liquid for each gramme of solid material. In general, theamount of the liquid medium need not exceed 20 cm³ for each gramme ofsolid material and satisfactory results can be achieved using from 2 upto 10 cm³ of the liquid medium for each gramme of the solid supportmaterial.

It is preferred that, in addition to the support material and the liquidmedium, there is also present in the suspension which is spray-dried, asmall quantity of a material which either assists in the agglomerationof the particles of the support material or which gives a spray-driedsolid having improved resistance to attrition. For convenience, thismaterial will be referred to as an "attrition inhibitor". The attritioninhibitor is conveniently present as a solution in the liquid medium.The attrition inhibitor should be such that it does not have anappreciable adverse effect on the activity and/or stereospecificity of apolymerisation catalyst which is obtained from the supported transitionmetal composition which is formed using the spray-dried solid. If thespray-dried support material is subsequently suspended in a liquidmedium, the attrition inhibitor preferably should be such as to at leastminimise dispersion of the spray-dried support material into smallerparticles in the presence of the liquid medium in which the supportmaterial is suspended. Hence, the attrition inhibitor is preferablysoluble in the liquid medium used for the spray-drying step but isinsoluble, or of low solubility in any liquid medium in which the solidis suspended after effecting the spray-drying step.

The attrition inhibitor may be for example polystyrene,polymethylmethacrylate, polyvinylacetate, atactic polypropylene or an ABblock copolymer, for example, of t-butylstyrene/styrene. We haveobtained useful results using polystyrene and polymethylmethacrylate asthe attrition inhibitor. When the attrition inhibitor is polystyrene orpolymethylmethacrylate, the liquid medium is preferably an aromaticliquid, for example, toluene. After the spray-drying stage, thespray-dried solid which contains polystyrene or polymethylmethacrylateas the attrition inhibitor is preferably not contacted with an aromaticliquid but rather is suspended in an aliphatic liquid medium. The amountof the attrition inhibitor is preferably from 0.5 up to 10% by weightrelative to the support material and is conveniently from 0.5 up to 4%by weight relative to the support material.

Apparatus which may be used in the spray-drying step of the presentinvention is illustrated in the accompanying drawings, wherein:

in FIG. 1 there is given a cross-sectional elevation of a spray-dryingapparatus having an atomising nozzle; and

in FIG. 2 there is given a cross-sectional elevation of an alternativespray-drying apparatus having a spinning disc atomizer.

The suspension of the support material in the liquid medium may bespray-dried using conventional spray-drying techniques. Thus, thesuspension is passed through a suitable atomizer which creates a sprayor dispersion of droplets of the suspension, a stream of hot gas isarranged to contact the droplets and cause evaporation of the liquidmedium and the solid product which separates is collected. Suitableatomizers for producing droplets of the suspension include nozzleatomizers and spinning disc atomizers. The gas which contacts thedroplets may be any suitable gas and is preferably a gas which does notreact with the support material under the conditions of spray-drying. Itis generally preferred to use an oxygen- and water-free gaseous mediumin order to avoid the presence of undesirable materials in thespray-dried product. However, spray-drying of the support may beeffected in dry air or dry oxygen provided there is no reaction betweenoxygen and the support material under the conditions used for thespray-drying. A suitable gaseous medium for effecting spray-drying isnitrogen having a high degree of purity, but any other gaseous mediummay be used, particularly one which will have no deleterious effect onthe supported transition metal composition which is the final product ofthe present invention. Alternative gaseous materials which may be usedinclude hydrogen and the inert gases such as argon or helium.

If it is desired to prevent the ingress of oxygen-or particularly watervapour-containing materials into the spray-drying apparatus, it ispreferred to operate at a slightly elevated pressure, for example, atabout 1.2 kg/cm² absolute. Although the temperature may be below theboiling temperature of the liquid medium under the pressure conditionswhich exist within the spray-drying apparatus, the temperature should besuch as to cause sufficient evaporation of the liquid medium to dry atleast the outer surface of the droplets before they reach the wall, ordischarge point, of the spray-drying apparatus.

The temperature of the spray-drying may be any desired temperatureprovided this does not have any undue effect on the nature of the solidsupport material. In general, it is preferred that the temperature ofthe hot gas introduced into the spray-drying apparatus does not exceedabout 200° C. It is also preferred that the temperature of the droplets,or of the spray-drying material obtained, does not exceed about 200° C.and preferably does not exceed about 150° C. To achieve sufficientevaporation of the liquid medium in the droplets, it is preferred thatthe temperature of the gas is at least 80° C. In general, thespray-drying will be effected by using a suspension at ambienttemperature to produce the spray and evaporating the liquid from thespray by means of a hot gas which is introduced into the spray-dryingapparatus.

The hot gas may be arranged to pass either in a counter-current flowrelative to the droplets of the mixture or may be arranged to pass in acocurrent flow relative to the droplets of the mixture. Using acocurrent flow, the atomizer is typically located at the top of thespray-drying apparatus and the hot gas is introduced into the top of theapparatus and is removed from near the bottom of the apparatus. With acountercurrent flow, the atomizer is typically located at the bottom ofthe spray-drying apparatus and arranged to spray upwardly against acurrent of hot gas introduced into the top of the apparatus.

Some of the spray-dried solid collects at the bottom of the apparatus,from which it may be removed, preferably continuously, by suitable meanssuch as a star feeder valve, a screw conveyor, or in the hot gas stream.

The hot gas, which has been cooled by its passage through thespray-drying apparatus may be removed separately from the spray-dryingapparatus. The hot gas may be passed through a cyclone to removeentrained solid, and the solid removed in the cyclone may be added toany which is separately removed from the spray-drying apparatus. Thevapour of the liquid medium which is present in the hot gas is desirablycondensed in a suitable condenser, and the condensed liquid medium canbe re-used for mixing with the solid material and subsequent grinding.The gas may then be reheated and recirculated to the spray-dryingapparatus.

The conditions of spray-drying can be adjusted to give any desiredparticle size and it is preferred that essentially all, that is at least90%, of the particles of the final spray-dried material are in the rangefrom 5 up to 100 microns, particularly between 10 and 80 microns, forexample having a mean size of about 30 microns.

Since the spray-dried solid material is subsequently contacted with atleast one compound of a transition metal to give a product which can beused as a component of a polymerisation catalyst, it is desirable thatthe form of the spray-dried solid material should be such that thepolymer obtained has a satisfactory particle form.

After effecting the spray-drying step, the spray-dried support materialis contacted in a subsequent stage with a transition metal compound toform a supported transition metal composition. The treatment with thetransition metal compound may be effected directly after thespray-drying stage or other intermediate treatment stages may be carriedout prior to effecting the treatment with a transition metal compound.

The transition metal compound is one in which the transition metal maybe for example vanadium or zirconium and is preferably titanium.Preferred transition metal compounds are the halides or oxyhalides, forexample, vanadium tetrachloride, vanadium oxytrichloride, zirconiumtetrachloride and especially preferred are the titanium halides, inparticular, titanium tetrachloride. More than one compound of atransition metal may be used such as a mixture of titanium halide andvanadium halide, for example, a mixture of vanadium tetrachloride andtitanium tetrachloride. If more than one transition metal compound isused, the treatment with the transition metal compound may be effectedin more than one stage or all of the transition metal compounds may beused in a single stage. The particular transition metal compounds whichare contacted with the spray-dried support material will be dependent onthe intended use of the supported transition metal composition. Thesupported transition metal compositions obtained by the process of thepresent invention are suitable for use as components of polymerisationcatalysts, particularly for the polymerisation of olefin monomers and,if the system is to be used for the polymerisation of the higher olefinmonomers, it is preferred that the transition metal compound is titaniumtetrachloride. However, if the supported transition metal composition isto be used for the production of an ethylene polymer in which the majorcomponent is ethylene, then a mixture of transition metal compounds maybe used in order to achieve variations in the molecular weightdistribution of the final polymer. However, for the polymerisation ofethylene, satisfactory results have been achieved using titaniumtetrachloride as the transition metal compound.

The treatment with the transition metal compound is convenientlyeffected by suspending the spray-dried support material in a liquidmedium which is, or which contains, the transition metal compound. Anumber of transition metal compounds are liquids, for example, titaniumtetrachloride, and using such liquid transition metal compounds thespray-dried support material is conveniently suspended in the undilutedliquid transition metal compound. It will be appreciated that if thespray-dried support material is suspended in a liquid transition metalcompound, there will be a substantial excess of the transition metalcompound relative to the support material. Alternatively, thespray-dried support material may be suspended in a liquid medium whichcomprises a solution of the transition metal compound in a suitablesolvent. If the spray-dried support material is suspended in a solutionof the transition metal compound, the proportion of the transition metalcompound to the solid material may be varied from about 0.1 millimolesof the transition metal compound for each gramme of the solid materialup to a substantial excess, that is, more than one mole per mole, of thetransition metal compound relative to the solid support material. Theprocedure used will depend on the way in which the supported transitionmetal composition is to be used but, in general, we prefer to carry outthis stage by suspending the spray-dried solid material in a liquidtransition metal compound.

The treatment of the spray-dried support material with the transitionmetal compound is preferably effected at an elevated temperature and, inparticular, at a temperature of at least 60° C. The treatment may beeffected at any temperature up to the boiling temperature of the liquidmedium in which the solid is suspended and thus temperature of up to200° C. may be used. If the solid is suspended in the liquid transitionmetal compound this may be effected at a temperature of up to the refluxtemperature of the transition metal compound, and when titaniumtetrachloride is used this temperature is about 137° C. In general,however, a temperature of from about 80° C. up to 120° C. is suitable.

Some transition metal compounds which may be contacted with thespray-dried support material may be compounds having a reduced stabilityat elevated temperature. If such a compound is used it will beappreciated that contacting of this compound with the spray-driedsupport material should be effected at a low temperature so that thereis no substantial deterioration or decomposition of the transition metalcompound.

It will also be appreciated that if desired the spray-dried solid may becontacted as a dry solid with a gaseous stream containing the vapour ofthe transition metal compound and such a treatment may be effected at atemperature in the range previously indicated for treatments with aliquid medium containing the transition metal compound.

The treatment of the spray-dried solid material with the transitionmetal compound is effected for a period of time which is sufficient toallow a desired extent of reaction between the transition metaa compoundand the support. In general, it is sufficient to allow the transitionmetal compound to remain in contact with the spray-dried supportmaterial for a period of from 5 minutes up to 20 hours and typicallyfrom 1 up to 5 hours.

The spray-dried support material may be subjected to more than onetreatment with the transition metal compound, and such treatments may beeffected using the same or a different transition metal compound. Aprocedure in which a support material is treated in two stages with thesame transition metal compound is described in our Specification BritishPatent 2,103,627A entitled "Transition Metal Composition, Production andUse".

After the treatment with the transition metal compound, depending on therelative proportions of transition metal compound and spray-driedsupport material which are used, the supported transition metalcomposition may be separated from the liquid medium and optionallywashed several times to remove at least some unreacted transitioncompound from the supported transition metal composition. The supportedtransition metal composition may be finally suspended in a suitableliquid medium or may be obtained as a dry solid.

In addition to the stages hereinbefore described, the production of thesupported transition metal composition may involve additional stages.Thus, a solid material which is the support material, the spray-driedsupport material or the transition metal composition, may be treatedwith one or more other reagents. The other reagents which may be used inthe additional stages include organo-metallic compounds,halogen-containing compounds, and/or Lewis Base compounds. The nature ofthe other reagents used will depend on the nature of the final supportedtransition metal composition which is desired and, in particular, theuse for which the supported transition metal composition is intended.

If the support material is an inorganic oxide such as silica or alumina,this may be used to produce a catalyst system of the type described inEuropean Patent Application Publication Nos. 14523 and 14524. In theprocedure of the foregoing European Patent Applications, a supportmaterial is treated with an organic magnesium compound, optionally witha halogen-containing compound, and with a Lewis Base compound and alsowith a transition metal compound. Thus, the process of the presentinvention may include a treatment of the support material, before orafter the spray-drying stage, with an organic magnesium compound, achlorine-containing compound and a Lewis Base compound, such treatmentsbeing in addition to the treatment with the transition metal compoundwhich is effected after the spray-drying stage. Thus, it will beappreciated that the spray-drying of the support material and subsequenttreatment thereof with a transition metal compound may be used as a partof the procedure described in European Patent Application PublicationNos. 14523 and 14524.

Alternatively, the spray-drying process of the present invention may beused as part of the procedure described in European Patent ApplicationPublication No. 15048. According to European Patent ApplicationPublication No. 15048, a magnesium hydrocarbyl compound is reacted witha halogenating agent, the halogenated product is treated with a LewisBase compound and this treated product is contacted with titaniumtetrachloride. Either of the intermediate products can be spray-dried inaccordance with the present invention and thereafter subjected to thesubsequent stages, including the treatment with titanium tetrachloride.

Particularly useful catalyst systems for the polymerisation of propylenein high yield to give a polymer of high stereospecificity may beobtained using a magnesium halide such as magnesium chloride as asupport material. Preferred catalyst systems of this type also include aLewis Base component. In the process of the present invention the LewisBase compound may be contacted with the support material before or afterthe latter has been subjected to the spray-drying stage. Usefulcatalysts are obtained by co-grinding the magnesium halide with a LewisBase compound. It will be appreciated that, if the support material isground with a Lewis Base compound, such a grinding stage should beeffected before the spray-drying stage is effected. Alternatively, thesupport material may be contacted with the Lewis Base compound withoutcarrying out a grinding stage. It will be appreciated that such aprocedure is particularly useful if the spray-dried support material iscontacted with the Lewis Base compound.

Thus, as a particular preferred embodiment of the present invention, asupport material which is magnesium chloride is suspended in a liquidmedium, the suspension is spray-dried, spray-dried magnesium chloride iscollected and thereafter treated with liquid undiluted titaniumtetrachloride at a temperature of at least 60° C. wherein before orafter effecting the spray-drying stage and before contacting thespray-dried support material with the liquid titanium tetrachloride, thesupport material is contacted with a Lewis Base compound.

Treatment with a Lewis Base compound is a preferred additional stage inthe process of the present invention. Any Lewis Base compound,especially an organic Lewis Base compound, which has been previouslyproposed for use in an olefin polymerisation catalyst system may beused. Thus, the Lewis Base compound may be an ether, an ester, a ketone,an alcohol, an orthoester, a sulphide (a thioether), an ester of athiocarboxylic acid (a thioester), a thioketone, a thiol, a sulphone, asulphonamide, a fused ring compound containing a heterocyclic sulphuratom, an organic silicon compound such as a silane or a siloxane, anamide such as formamide, urea and substituted derivatives thereof suchas tetramethyl urea, thiourea, an alkanolamine, an amine, which termincludes a cyclic amine, a diamine, or a polyamine, for example,pyridine, quinoline, or tetramethylethylenediamine, or an organicphosphorous compound such as an organic phosphine, an organic phosphineoxide, an organic phosphite or an organic phosphate. The use of organicLewis Base compounds is disclosed, inter alia, in British PatentSpecification Nos. 803 198, 809 717, 880 998, 895 509, 920 118, 921 954,933 236, 940 125, 966 025, 969 074, 971 248, 1 013 363, 1 017 977, 1 049723, 1 122 010, 1 150 850, 1 208 815, 1 234 657, 1 324 173, 1 359 328, 1383 207, 1 387 890, 1 423 658, 1 423 659, 1 423 660, 1 495 031, 1 527736, 1 554 574 and 1 559 194.

Lewis Bases which have been disclosed as being particularly useful inpolymerisation catalyst components particularly supported transitionmetal compositions include esters and organic silicon compounds. Theesters may be the esters of saturated or unsaturated carboxylic acids,for example, ethyl acetate or methyl methacrylate, but we particularlyprefer to use the esters of carboxylic acids which contain an aromaticgroup such as, for example, ethylbenzoate, butylbenzoate, methylp-methylbenzoate, ethyl p-methoxybenzoate and ethyl phenylacetate. Otheresters which may be used are the mono- and poly-esters of saturated andunsaturated polycarboxylic acids (which term includes dicarboxylicacids) such as dialkyl phthalates. Organic silicon compounds can becompounds containing one or more Si--OR, Si--OCOR or Si--NR₂ bonds,where R is a hydrocarbyl group, and include phenyltriethoxy-silane,diphenyldiisobutoxysilane and isobutyl-triethyoxysilane.

The treatment of the support material with the Lewis Base compound maybe effected by grinding, for example, as disclosed in British PatentSpecification Nos. 1,527,736 and 1,559,194. Alternatively, the supportmaterial, which may optionally have been subjected to other treatments,may be treated either before or after the spray-drying stage bycontacting with the Lewis Base compound in the absence of milling, forexample, as described in British Patent Specification No. 1 271 411 andEuropean Patent Application Publication Nos. 14523, 14524 and 15048.

The process of the present invention may be included in the process ofour British Patent Specification No. 2,103,627A "Transition MetalComposition, Production and Use". In the process of our said copendingapplication, a composition of a magnesium halide and an ester of acarboxylic acid is formed, typically by cogrinding the magnesium halideand the ester, the composition is contacted with hot titaniumtetrachloride, the contacting with hot titanium tetrachloride isrepeated and thereafter the product obtained is subjected to a mildwashing procedure which is sufficient to remove only a part of thesoluble titanium species from the product. The preferred transitionmetal composition is obtained by cogrinding magnesium chloride withethyl benzoate, suspending the coground product in titaniumtetrachloride at a temperature of at least 60° C., separating the solidfrom the titanium tetrachloride, repeating the treatment with thetitanium tetrachloride and washing the product obtained not more thantwice with heptane at a temperature of at least 60° C. In the titaniumchloride composition thus obtained, a substantial proportion, which maybe more than 50% of the titanium, may be capable of being extracted bycontinued washing with hot heptane.

Alternatively, the process of the present invention may be included inthe process of our copending patent application Ser. No. 444,364entitled "Composition Production and Use". In accordance with copendingpatent application Ser. No. 444,364 a titanium-containing composition isobtained by contacting a magnesium halide with at least one compound ofa non-metallic element, other than oxygen, of Group IV or VI of thePeriodic Table, and contacting the product obtained with a liquid phasecontaining titanium tetrachloride, where the compound of thenon-metallic element also contains oxygen and halogen, there being oneor two atoms of oxygen for each molecule and sufficient halogen tosatisfy the residual valencies of the non-metallic element which may becarbon, phosphorus or sulphur. It is preferred that the magnesium halidematerial is also contacted with a Lewis Base compound, for example anester such as ethyl benzoate. The compound of the non-metallic elementwill hereinafter be referred to as the "non-metallic halide" and istypically thionyl chloride (SOCl₂). In accordance with the preferredprocedure of copending patent application Ser. No. 444,364 the magnesiumhalide is ground with thionyl chloride and an ester such as ethylbenzonate, subsequently suspended at least once in undiluted titaniumtetrachloride at a temperature of at least 60° C. and washed at leastonce with an inert hydrocarbon such as heptane at a temperature of atleast 60° C. The spray-drying procedure of the present invention may beincorporated into the procedure of copending patent application Ser. No.444,364 at any stage before the stage in which the magnesium halide issuspended in titanium tetrachloride.

The solid support material may be spray-dried without being subjected toany preliminary treatment other than possibly being milled with a LewisBase compound and/or a non-metallic halide. However, the particle size,and particle size distribution, of the solid support material may besuch that the solid support material does not readily spray dry or doesnot give a spray dried product having a satisfactory particle form.Thus, it may be necessary to treat the solid support material to improveits particle form and/or size. The solid support material may be treatedby the process described in our copending application Ser. No. 405,493,entitled "Spraying Solid". According to the process of our saidcopending application, a solid material, which may be a solid supportmaterial, is mixed with a liquid medium and the mixture is subjected tomechanical action to cause a reduction in the particle size of the solidmaterial, and the resulting material is spray dried. The mechanicalaction can be such as to subject a suspension of the support material inthe liquid medium to simultaneous vigorous agitation and a shearingaction. Alternatively, the mechanical action can be achieved by grindingthe mixture of the solid support material and the liquid medium. Theprocedures of our said copending application may be used as apreliminary stage in the process of the present invention, as describedin more detail in the Examples.

The supported transition metal composition obtained by the process ofthe present invention, including the additional treatment stages notedherein, may be used together with an organic compound of anon-transition metal to give a polymerisation catalyst system.

Thus, as a further aspect of the present invention, there is provided apolymerisation catalyst system which is the product obtained by mixingtogether

(1) a supported transition metal composition obtained by the processhereinbefore described; and

(2) an organic compound of a non-transition metal of Groups I to IV ofthe Periodic Table.

Component 2 of the catalyst may be an organo-metallic derivative of ametal of Groups IA, IIA, IIB, IIIB, or IVB of the Periodic Table. Theorgano-metallic compound is typically an organic compound of aluminiumor of a metal of Group IIA of the Periodic Table or a complex of anorganic compound of a metal of Group IA or IIA of the Periodic Tabletogether with an organic aluminium compound. Thus, Component 2 of thecatalyst system may be an organic magnesium compound such as, forexample, a dihydrocarbyl magnesium compound, a hydrocarbyl magnesiumhalide compound or an alkoxy magnesium compound, preferably onecontaining an alkyl group in addition to an alkoxy group. Alternatively,a complex of a magnesium compound with an aluminium compound may beused, for example a complex of a magnesium alkyl with an aluminiumalkyl.

Component 2 may be a complex of a metal of Group IA with an organicaluminium compound, for example, a compound of the type lithiumaluminium tetraalkyl.

Preferably Component 2 is an organic aluminium compound which may be,for example, an aluminium hydrocarbyl sulphate, or an aluminiumhydrocarbyl hydrocarbyloxy or, more preferably, an aluminium hydrocarbylhalide such as dihydrocarbyl aluminium halide or particularly preferredare aluminium trihydrocarbyl compounds or dihydrocarbyl aluminiumhydrides. The especially preferred aluminium compounds are aluminiumtrialkyls particularly those in which the alkyl group contains from 2 upto 10 carbon atoms, for example, aluminium triethyl, aluminiumtri-isobutyl and aluminium trioctyl.

The catalyst system may consist of only two components, particuarly ifthe monomer being polymerised is ethylene or contains a substantialproportion of ethylene, for example, sufficient to give a polymercontaining at least 70% by weight of ethylene. However, if Component 2of the catalyst system is an aluminium trihydrocarbyl compound, and thecatalyst system is to be used to polymerise a higher olefin monomer suchas propylene, it is preferred that the catalyst system also includes aLewis Base compound. The Lewis Base compound which may be used as afurther component of the catalyst system can be any Lewis Base compoundof the type disclosed herein as being suitable for use in the productionof a transition metal composition in accordance with the presentinvention.

Particularly preferred Lewis Base compounds for use as a furthercomponent of the catalyst system are esters and organic siliconcompounds such as the esters of carboxylic acids which contain anaromatic group such as, for example, ethyl benzoate, butyl benzoate,methyl p-methylbenzoate, ethyl p-methoxybenzoate, and ethylphenylacetate, and also dialkyl phthalates and phenyl alkoxysilanes.

In addition to, or instead of, the Lewis Base compound which may bepresent as a further component of the catalyst system, there may also bepresent in the catalyst system a substituted or unsubstituted polyene,which may be an acyclic polyene such as 3-methylheptatriene (1,4,6), ora cyclic polyene such as cyclooctatriene, cyclooctatetraene, orcycloheptatriene, or the alkyl- or alkoxy-substituted derivatives ofsuch cyclic polyenes, or the the tropylium salts or complexes, ortropolone or tropone.

The proportions of Components 1 and 2 of the catalyst system can bevaried within a wide range as is well known to the skilled worker. Theparticular preferred proportions will be dependent on the type ofmaterials used and the absolute concentrations of the components but, ingeneral, we prefer that for each gramme atom of the transition metalwhich is present in Component 1 of the catalyst system there is presentat least one mole of Component 2. The number of moles of Component 2 foreach gramme atom of the transition metal in Component 1 may be as highas 1000 but conveniently does not exceed 500 and with some transitionmetal compositions may be not more than 25, for example, from 5 up to10.

When catalyst system includes Lewis Base component as a furthercomponent of the catalyst system, it is preferred that this Lewis Basecompound is present in an amount of not more than 1 mole for each moleof Component 2 and particularly in an amount of from 0.1 up to 0.5 molesof the Lewis Base compound for each mole of Component 2. However,depending on the particular organic metal compound and Lewis Basecompound, the proportion of the Lewis Base compound may need to bevaried in order to achieve the optimum catalyst system.

If the catalyst system includes a polyene, it is preferred that thepolyene is present in an amount of not more than 1 mole for each mole ofComponent 2, and especially from 0.01 up to 0.20 moles for each mole ofComponent 2. If the catalyst system includes both the Lewis Basecomponent and the polyene, it is preferred that both of these materialsare present together in an amount of not more than 1 mole for each moleof Component 2.

Catalyst systems in accordance with the present invention are suitablefor the polymerisation and copolymerisation of unsaturated monomers,particularly ethylenically unsaturated hydrocarbon monomers such as theolefine monomers.

Thus, as a further aspect of the present invention, there is provided aprocess for the production of a polymer or copolymer of an unsaturatedmonomer wherein at least one ethylenically unsaturated hydrocarbonmonomer is contacted under polymerisation conditions with apolymerisation catalyst as hereinbefore defined.

The monomer which may be contacted with the catalyst system isconveniently one having the following formula:

    CH.sub.2 ═CHR.sup.1

wherein R¹ is a hydrogen atom or a hydrogen radical.

Thus, the monomer may be ethylene, propylene, butene-1, pentene-1,hexene-1, 4-methylpentene-1, styrene, 1,3-butadiene or any other monomerwhich satifies the foregoing formula. The monomer is preferably anolefin monomer, particularly an aliphatic mono-olefin monomer containingnot more than 10 carbon atoms.

The monomers may be homopolymerised or may be copolymerised together. Ifpropylene is copolymerised it is preferred to effect thecopolymerisation with ethylene, conveniently using a sequentialcopolymerisation process as is described in British PatentSpecifications Nos. 970,478; 970,479 and 1,014,944. If ethylene is beingcopolymerised using the process of the present invention, it ispreferred to carry out the copolymerisation using a mixture of ethyleneand the desired comonomer, for example butene-1 or hexene-1, wherein themixture of monomers has essentially the same composition throughout thepolymerisation process.

Component 1 of the catalyst may be mixed with the other component, orcomponents, of the catalyst in the presence of the olefin monomer. Ifthe catalyst includes a Lewis Base compound, it is preferred to premixthe organic metaa compound which is component 2 with the Lewis Basecompound and then to mix this pre-mixture with the reaction productwhich is component 1.

As is well known, Ziegler-Natta type catalysts are susceptible to thepresence of impurities in the polymerisation system. Accordingly, it isdesirable to effect the polymerisation using a monomer, and a diluent ifthis is being used, which has a high degree of purity, for example amonomer which contains less than 5 ppm by weight of water and less than1 ppm by weight of oxygen. Materials having a high degree of purity canbe obtained by processes such as those described in British PatentSpecifications Nos. 1,111,493; 1,226,659 and 1,383,611.

Polymerisation can be carried out in the known manner, for example inthe presence or absence of an inert diluent such as a suitably purifiedparaffinic hydrocarbon, in the liquid phase using an excess of theliquid monomer as the polymerisation medium or in gas phase, this latterterm being used herein to mean the essential absence of a liquid medium.

If polymerisation is effected in gas phase, it may be effected byintroducing the monomer, for example propylene, into the polymerisationvessel as a liquid and operating with conditions of temperature andpressure within the polymerisation vessel which is such that the liquidmonomer vaporises, thereby giving an evaporative cooling effect, andessentially all of the polymerisation occurs with a gaseous monomer.Polymerisation in gas phase may be effected using conditions which aresuch that the monomer is at a temperature and partial pressure which areclose to the dew point temperature and pressure for that monomer, forexample as described in more detail in British Patent Specification No.1,532,445. Polymerisation in gas phase can be effected using anytechnique suitable for effecting a gas-solid reaction such as afluidised-bed reactor system, a stirred-bed reactor system or a ribbonblender type of reactor.

Using the catalyst systems of the present invention, ethylene may bepolymerised or copolymerised, for example with butene-1 as thecomonomer, in a fludised-bed reactor system to give a high yield ofpolymer. The fluidising gas is the gas mixture to be polymerisedtogether with any hydrogen which is present as a chain transfer agent tocontrol molecular weight. Thus, for the copolymerisation of ethylene andbutene-1 to produce an ethylene copolymer having a density of less thanabout 940 kg/m³, the gas composition is typically from 50 to 60 mole %ethylene, 15 to 25 mole % butene-1 with the remainder, apart from inertmaterials and impurities, being hydrogen.

Polymerisation may be effected either in a batch manner or on acontinuous basis, and the catalyst components may be introduced into thepolymerisation vessel separately or all the catalyst components may bemixed together before being introduced into the polymerisation reactor.If all of the catalyst components are pre-mixed, this pre-mixing ispreferably effected in the presence of a monomer and such pre-mixingwill result in at least some polymerisation of this monomer before thecatalyst system is introduced into the polymerisation vessel. If thepolymerisation is being carried out in the gas phase, the catalystcomponents may be added to the polymerisation reactor suspended in astream of the gaseous monomer or monomer mixture.

The polymerisation can be effected in the presence of a chain transferagent such as hydrogen or a zinc dialkyl, in order to control themolecular weight of the product formed. If hydrogen is used as the chaintransfer agent in the polymerisation of propylene, it is convenientlyused in an amount of from 0.01 up to 5.0%, particularly from 0.05 up to2.0% molar relative to the monomer. When the monomer being polymerisedis ethylene, or a mixture in which ethylene is a major polymerisablecomponent (by moles), the amount of hydrogen used may be greater, forexample, in the homopolymerisation of ethylene the reaction mixture maycontain in excess of 50% molar of hydrogen, whereas if ethylene is beingcopolymerised, a proportion of hydrogen which is typically up to 35%molar is used. The amount of chain transfer agent will be dependent onthe polymerisation conditions, especially the temperature, which, atpolymerisation pressures not exceeding 50 kg/cm², is typically in therange from 20° C. up to 100° C., preferably from 50° C. up to 85° C.

Polymerisation can be effected at any pressure which has been previouslyproposed for effecting the polymerisation of monomers such as olefinmonomers. However, although the polymerisation may be effected atpressures up to 3000 kg/cm², at which pressures the polymerisationtemperature may be as high as 300° C., it is preferred to carry out thepolymerisation at relatively low pressures and temperatures. Whilst thepolymerisation may be effected at atmospheric pressure, it is preferredto use a slightly elevated pressure and thus it is preferred that thepolymerisation is effected at a pressure of from 1 kg/cm² up to 50kg/cm², preferably from 5 up to 30 kg/cm². The polymerisationtemperature is preferably above ambient temperature and typically willnot exceed 100° C.

Referring to FIG. 1 of the accompanying drawings, a gas-tightspray-drying vessel 1 comprises an upper cylindrical section 2 and alower, generally conical section 3. The upper section 2 is provided witha cover plate 4.

An atomizer nozzle assembly 5 is located within a plenum chamber 6, theplenum chamber 6 being mounted on the cover plate 4. The atomizer nozzleassembly 5 contains an inner conduit 7 and an outer conduit 8. Theconduit 7 is a continuation of a conduit 9, which is connected to asource (not shown) of a suspension containing, for example, a groundmixture of a solid support material and a liquid medium. Conduit 8 isconnected to a source (not shown) of an inert gas. The conduits 7 and 8are essentially co-axial and are tapered at their lower ends. The nozzleassembly 5 is provided at its lower end with an orifice 10 formed byopenings in both of conduits 7 and 8. A conduit 11 is connected to theplenum chamber 6 and also to a source (not shown) of a heated inert gas.

Near the bottom of the vessel 1 is located a conduit 12 which passes outof the vessel 1 through the side of the conical section 3. A conduit 13,in which is located a valve means 14, is connected to the bottom of theconical section 3 and is also connected to a hopper (not shown) forstoring dry solid.

In operation, the gas flow through the conduit 8 draws the suspensionthrough the conduits 9 and 7. The gas and the suspension pass throughthe orifice 10 and form a spray of droplets. Hot inert gas which passesthrough conduit 11 and plenum chamber 6 flows past the orifice 10 andcauses evaporation of the liquid medium from the droplets of thesuspension. The inert gas containing the vaporised liquid medium andsome entrained spray-dried solid, passes out of the vessel 1 through theconduit 12. The major portion of the spray-dried solid collects at thebottom of the conical section 3 from which it is withdrawn through theconduit 13 by operation of the valve means 14.

The inert gas passed through the conduit 11 is conveniently nitrogen ata temperature in the range 130° to 150° C.

The apparatus shown in FIG. 2 is essentially the same as that shown inFIG. 1 with the exception that the atomizer nozzle is replaced by a discatomizer. In FIG. 2, the corresponding parts are indicated by the samereference numbers as in FIG. 1.

A disc atomizer 15 mounted on the end of an output shaft 16 of a highspeed gear box/motor assembly 17 is located near the top of thevessel 1. The disc 15 consists of two plates 18 and 19 between which aresecured a series of radial vanes 20. A chamber 21 surrounds the driveshaft 16 and extends to the upper plate 18 of the disc 15. The plate 18is provided with a central opening indicated at 22.

The plenum chamber 6 surrounds the chamber 21. A conduit 23 is connectedto the chamber 21 and also to a source (not shown) of a suspensioncontaining a solid material.

In operation, the disc 15 is rotated at a high speed in the range from500 up to 25,000 rpm. A suspension which is a mixture of a solid supportmaterial and an inert liquid medium, for example a magnesiumchloride-ethyl benzoate product in toluene, is passed through theconduit 23 and chamber 21 into the space between the plates 18 and 19 ofthe disc 15. The high speed of rotation of the disc 15, and the vanes20, cause the suspension to pass to the periphery of the disc 15 fromwhich the suspension is flung off as a spray of droplets.

A hot inert gas, for example nitrogen in the range 130° C. to 150° C.,is passed through the conduit 11, and plenum chamber 6 to flow round therotating disc 15. The hot inert gas causes evaporation of the liquidmedium from the droplets of the suspension.

The inert gas containing the vaporised liquid medium and some entrainedspray-dried solid, passes out of the vessel 1 through the conduit 12.The major portion of the spray-dried solid collects at the bottom of theconical section 3 from which it is withdrawn through the conduit 13 byoperation of the valve means 14.

The inert gas passing through the conduit 12 may be passed to a cyclone(not shown) to recover entrained solid, then to a condenser (not shown)to recover the liquid vapour and finally to a re-heater (not shown). Thereheated inert gas is then recirculated to the conduit 11. Thespray-dried solid passing through the conduit 13 is passed to a storagehopper (not shown).

Other alternative arrangements and spray-drying techniques will beapparent to the skilled worker and may be used without departing fromthe scope of the present invention as defined herein.

Various aspects of the present invention will now be described withreference to the following Examples which are illustrative of theinvention. In the Examples, all operations are effected under anatmosphere of nitrogen unless otherwise indicated. All the glassapparatus was dried in an air oven at 120° C. for at least one hour andpurged with nitrogen before use.

Examples 1 to 6 illustrate spray-drying a solid support material andcontacting the spray-dried solid with a transition metal compound, inaccordance with the present invention, and the incorporation of thisprocedure into the preparation of a transition metal composition carriedout in accordance with our British Patent Specification No. 2,103,627Aentitled "Transition Metal Composition, Production and Use". In Examples1 to 6, the solid support material was subjected to a mechanical actionas described in our copending application, Ser. No. 405,983 entitled"Spraying Solid".

EXAMPLE 1 (A) Milling magnesium chloride and ethyl benzoate

A Siebtechnik SM10 Vibromill having a total volume of about 38 dm³ andcontaining 119 kg of stainless steel balls of 25 mm diameter was sealed,and purged with nitrogen to give a nitrogen atmosphere in the mill. Amixture of water and ethylene glycol at 0° C. was passed through thejacket of the mill and the mill was vibrated at a frequency of 1500oscillations per minute and an amplitude of 2 mm. Four kilogrammes ofessentially anhydrous magnesium chloride (BDH technical grade) wereintroduced into the mill whist the mill was being vibrated. After theaddition of the magnesium chloride, the mill was vibrated for about 15minutes and 2 dm³ of ethyl benzoate were added to the vibrating millover a period of about 15 minutes. The mill was then vibrated for afurther 24 hours whilst continuing to pass the mixture of water andethylene glycol at 0° C. through the jacket of the mill.

After 24 hours, the mill was inverted, the inverted mill was vibratedand the milled magnesium chloride-ethyl benzoate was collected undernitrogen. The molar ratio of magnesium chloride to ethyl benzoate in themill was about 3 to 1.

(B) Dispersion of milled magnesium chloride-ethyl benzoate

A one dm³ three-necked glass flask having a heating/cooling jacket, wasfitted with a high shear homogeniser of the Ultra Turrax T45 type(available from Janke and Kunkel KG IKA Werke). Into the flask wereintroduced 630 g of nitrogen sparged toluene, 245 g of the milledmaterial obtained in stage (A) and 1.62 g of polystyrene ("Lustrex" HF66--available from Monsanto Limited). Water at ambient temperature waspassed through the heating/cooling jacket. The mixture was thensubjected simultaneously to vigorous agitation and shearing by operatingthe homogeniser for five minutes at maximum power (an initial rate ofstirring of 10,000 rpm). During the agitation and shearing, thetemperature of the mixture rose but did not exceed 50° C.

The dispersion was then transferred to a storage vessel (a 2 dm³three-necked glass flask fitted with a stirrer) and, whilst stirring, afurther 0.8 g of polystyrene was added. The mixture was stirred for afurther 30 minutes.

(C) Spray-drying of magnesium chloride-ethyl benzoate dispersion

The dispersion obtained in stage (B) was spray-dried using a glasslaboratory scale spray-drying apparatus similar to that illustrated inFIG. 1 of the drawings and previously described herein. The spray-dryingapparatus had a diameter of 15 cm and a length of 0.7 meters, theconical section 3 was replaced by a generally hemispherical bottomsection, the conduit 12 was omitted, the valve 14 in the conduit 13 wasomitted and the conduit 13 was connected directly to a cyclone providedwith a catch-pot in which the solid material was collected. The spraynozzle used was a 1/4 JAU Automatic Air Atomizing Nozzle obtained fromSpraying Systems Co. of the USA and having a 0.52 mm diameter nozzle.

Spraying was effected under nitrogen by passing a stream of nitrogen,preheated to a temperature of 130° C., through conduit 11 at a rate of190 dm³ /minute. Nitrogen at a pressure of about 0.5 kg/cm² gauge wasintroduced into the spray nozzle through conduit 8. The suspensionobtained in stage (B) was fed from the 2 dm³ three-necked glass flask tothe spray nozzle by the application of an excess nitrogen pressure of0.07 kg/cm² to this flask.

(D) Contacting with titanium tetrachloride

100 grammes of the spray-dried product from stage C were transferred toa two dm³ jacketted glass vessel which was provided with a stirrer. Onedm³ of titanium tetrachloride were added to the vessel, the stirrer wasstarted and heating was applied to the jacket. Heating was continueduntil a temperature of 100° C. was attained, which took 0.5 hours. Thetemperature was maintained at 100° C., and stirring was continued, forthree hours. At the end of three hours, the stirrer was stopped and thesolid was allowed to settle whilst continuing to heat the contents ofthe vessel. Two hours after terminating the stirring, the supernatantliquid was siphoned off from the settled solid. The heating was switchedoff and the contents of the vessel allowed to cool by standingovernight.

The contacting with the titanium tetrachloride was repeated by addingone dm³ of titanium tetrachloride to the cold residue remaining from theprevious contacting, the conditions of treatment being as previouslydescribed.

(E) Washing

To the residue remaining from stage (D) was added 1.5 dm³ of a heptanefraction, at least 90% of which is n-heptane (hereafter referred to asthe "n-heptane fraction") at ambient temperature. The mixture wasstirred and heated up to reflux temperature (about 100° C.). Stirring atreflux temperature was continued for an hour and then ceased. After afurther 30 minutes, the supernatant liquid was siphoned off from thesettled solid whilst still heating.

After ten minutes, a further 1.5 dm³ of the n-heptane fraction atambient temperature was added to the hot residue and the mixture washeated up to 100° C. and was stirred at that temperature for one hour.The stirrer was switched off and the solid allowed to settle. After onehour, the supernatant liquid was siphoned off from the settled solid.The heater was switched off and the settled solid allowed to coolovernight.

To the residue remaining from the previous washing step was added onedm³ of the n-heptane fraction at ambient temperature. The mixture wasstirred for 15 minutes without heating and allowed to settle. After 35minutes the supernatant liquid was siphoned off from the settled solid.This procedure was repeated once.

The cold residue remaining from the fourth washing step was diluted withthe n-heptane fraction to give a final volume of one dm³ and the mixturewas transferred to a storage vessel under nitrogen.

A sample (5 cm³) of the mixture was treated with 2N sulphuric acid andthe aqueous layer was subjected to spectrophotometric analysis. Themixture was found to contain 2.7 milligramme atoms of titanium/dm³, 72milligramme atoms of magnesium and 160 milligramme atoms ofchloride/dm³. The solid component had a titanium content of 1.64% byweight.

EXAMPLE 2 (A) Milling magnesium chloride and ethyl benzoate

A Siebtechnik SM 6 Vibromill chamber having a total usable volume ofabout 1.5 dm³ and containing 180 stainless steel balls of 25 mm diameterwas sealed, evacuated to a pressure of 0.3×10⁻³ kg/cm² and purged withnitrogen to give a nitrogen atmosphere in the mill. A mixture of waterand ethylene glycol at 0° C. was passed through the jacket of the milland the mill was vibrated at a frequency of 1500 oscillations per minuteand an amplitude of 2 mm. 182 grammes of essentially anhydrous magnesiumchloride (BDH technical grade) was incorporated into the mill chamberwhilst the mill was being vibrated. After the addition of the magnesiumchloride, the mill was vibrated for about 15 minutes and 91 cm³ of ethylbenzoate was then added to the vibrating mill over a period of about 5minutes. The mill was then vibrated for a further 24 hours whilstcontinuing to pass the mixture of water and ethylene glycol at 0° C.through the jacket of the mill.

(B) Milling with toluene

After 24 hours, 500 cm³ of toluene were added to the mill chamber whilstcontinuing to vibrate the mill. Milling was continued in the presence ofthe added toluene at 0° C. for a further three hours.

After three hours, the mill was inverted, the inverted mill was vibratedand the milled magnesium chloride-ethyl benzoate was collected undernitrogen. The mill chamber was washed out with 800 cm³ of toluene whichwas added to the suspension previously removed. The molar ratio ofmagnesium chloride to ethyl benzoate in the mill was about 3 to 1.

To the milled mixture, which was being stirred, was added a 10%weight/volume solution of polystyrene ("Styron" 686/7--available fromDow Chemical Company) in toluene to provide 2% by weight of polystyrenerelative to the milled magnesium chloride-ethyl benzoate.

After standing overnight, the mixture had set solid and it was necessaryto add a further quantity of toluene, and to agitate the mixture, inorder to resuspend the solid particles. The diluted mixture had a solidcontent of about 15% by weight.

(C) Spray drying magnesium chloride/ethyl benzoate suspension

All of the suspension obtained in step (B) was spray-dried using a glasslaboratory scale spray drying apparatus similar to that illustrated inFIG. 1 of the drawings and previously described herein. The spray dryingapparatus had a diameter of 15 cm and a length of 0.7 meters, theconical section 3 was replaced by a generally hemispherical bottomsection, the conduit 12 was omitted, the valve 14 in the conduit 13 wasomitted and the conduit 13 was connected directly to a cyclone providedwith a catch-pot in which the solid material was collected. The spraynozzle used was a 1/4 JAU Automatic Air Atomizing Nozzle obtained fromSpraying Systems Co. of the USA and having a 0.72 mm diameter nozzle.

Spraying was effected under nitrogen by passing a stream of nitrogen,preheated to a temperature of 140° to 150° C., through conduit 11 at arate of 170 to 180 dm³ /minute. Nitrogen at a pressure of about 1.4kg/cm² absolute was introduced into the spray nozzle. The suspensionobtained in step (B) was fed from a stirred storage flask to the spraynozzle by the application of an excess nitrogen pressure of 0.25 kg/cm²to the storage flask.

(D) Contacting with titanium tetrachloride

A sample (96 grammes) of the spray dried product from stage (C) wastransferred to a 1.8 dm³ jacketted glass vessel which was provided witha stirrer. One dm³ of titanium tetrachloride was added to the vessel,the stirrer was started and heating was applied to the jacket. Heatingwas continued until a temperature of 100° C. was attained, which took0.5 hours. The temperature was maintained at 100° C., and stirring wascontinued, for three hours. At the end of three hours, the stirrer wasstopped and the solid was allowed to settle whilst continuing to heatthe contents of the vessel. 4.0 hours after terminating the stirring,the supernatant liquid was siphoned off from the settled solid. Theheating was switched off and the contents of the vessel allowed to coolby standing overnight.

The contacting with the titanium tetrachloride was repeated by addingone dm³ of titanium tetrachloride to the cold residue remaining from theprevious contacting, the conditions of treatment being as previouslydescribed.

(E) Washing

To the residue remaining from stage (D) was added a sufficient quantityof the n-heptane fraction, at ambient temperature to give a total volumeof 1.5 dm³. The mixture was stirred and heated up to reflux temperature(about 100° C.). Stirring at reflux temperature was continued for anhour and then ceased. After a further 2.5 hours, the supernatant liquidwas siphoned off from the settled solid whilst still heating.

Heating was ceased and a sufficient quantity of the n-heptane fractionat ambient temperature was added to the hot residue to give a totalvolume of 1.5 dm³ at a temperature of about 45° C. The mixture wasstirred without heating for 15 minutes. The stirrer was switched off andthe solid allowed to settle. After 1.25 hours, the supernatant liquidwas siphoned off from the settled solid.

To the residue remaining from the previous washing step was added asufficient quantity of the n-heptane fraction at ambient temperature togive a total volume of 1.5 dm³ at ambient temperature. The mixture wasstirred for 15 minutes without heating and allowed to settle. After 1.25hours, the supernatant liquid was siphoned off from the settled solid.

The cold residue remaining from the third washing step was diluted withthe n-heptane fraction to give a final volume of 1.0 dm³ and the mixturewas transferred to a storage vessel under nitrogen.

EXAMPLE 3

The procedure of Example 2 was repeated with the changes notedhereafter.

In stage (A), 255 grammes of magnesium chloride and 32 cm³ of ethylbenzoate were used. The molar ratio of magnesium chloride to ethylbenzoate was about 12 to 1.

In stage (B), 400 cm³ of toluene were used and the mixture was milledfor 0.5 hours. The mill chamber was washed out with 300 cm³ of toluene.The mixture was allowed to stand overnight, without adding anypolystyrene, and the mixture was still fluid the following morning. Thepolystyrene solution was added, whilst stirring the mixture, to provide1.5% by weight of polystyrene relative to the milled magnesiumchloride-ethyl benzoate.

In stage (C), the heated nitrogen was passed at a rate of 190 dm³/minute. Nitrogen at a pressure of about 1.25 kg/cm² absolute wasintroduced into the spray nozzle. The excess pressure applied to thestorage flask was 0.14 kg/cm².

In stage (D), an 800 cm³ jacketted glass vessel with a stirrer was used.25.5 grammes of the spray-dried product from stage (C) were used and 255cm³ of titanium tetrachloride for each treatment with titaniumtetrachloride. At the end of the second treatment with titaniumtetrachloride, the solid was allowed to settle for 1.5 hours, thesupernatant liquid was removed but the mixture was not allowed to cool.

In stage (E), four washing steps were effected and each washing step waseffected using 300 cm³ of an aliphatic hydrocarbon consistingessentially of dodecane isomers and having a boiling point in the range170° C. to 185° C. (hereafter referred to simply as the "aliphatichydrocarbon"). The first and second washes were effected by heating themixture up to 100° C. and stirring at this temperature for one hour. Thefirst wash was effected by adding the aliphatic hydrocarbon to the hotresidue remaining after the second treatment with titaniumtetrachloride. The second wash was effected by adding the aliphatichydrocarbon to the hot residue remaining after the first wash. Heatingwas terminated after the second wash and the third wash was effected byadding the aliphatic hydrocarbon to the hot residue from the second wasand stirring for 15 minutes without heating. After removing thesupernatant liquid from the third wash, the mixture was allowed to coolovernight and the fourth was effected on the cold residue of the thirdwash. The residue was diluted to give a final volume of 255 cm³ usingthe aliphatic hydrocarbon.

EXAMPLE 4

The procedure of Example 3 was repeated with the changes notedhereafter.

In stage (A), 207 grammes of magnesium chloride and 52 cm³ of ethylbenzoate were used. The molar ratio of magnesium chloride to ethylbenzoate was about 6 to 1.

In stage (B), the mill chamber was washed out with 200 cm³ of toluene.After standing overnight, the mixture was still fluid but was viscous.After adding the polystyrene solution, a further 100 cm³ of toluene wereadded.

In stage (C), nitrogen at a pressure of about 1.35 kg/cm² absolute wasintroduced into the spray nozzle.

In stage (D), 25 grammes of the spray-dried product from stage (C) wereused and 250 cm³ of titanium tetrachloride for each treatment withtitanium tetrachloride. In each titanium tetrachloride treatment, thesolid was allowed to settle for about one hour before the supernatantliquid was siphoned off.

In stage (E), the washings were effected using the n-heptane fraction.The residue was allowed to cool overnight after the first hot wash. Thesecond hot wash was effected and the two cold washes were effected insuccession directly after the second hot wash. The residue was dilutedto give a final volume of 250 cm³ using the n-heptane fraction.

EXAMPLE 5

The procedure of Example 4 was repeated with the changes notedhereafter.

In stage (A), 212.4 grammes of magnesium chloride, 53.5 cm³ of ethylbenzoate and 53.5 cm³ of toluene were used. The molar ratio of magnesiumchloride to ethyl benzoate was about 6 to 1.

In stage (B), the mill chamber was washed out with 300 cm³ of toluene.The total suspension was split into two approximately equal portions. Toone portion of the suspension was added the polystyrene solution toprovide 2% by weight of polystyrene relative to the milled magnesiumchloride-ethyl benzoate. The suspension was diluted with a sufficientquantity of toluene to give a final suspension having a 25% by weightsolid content.

In stage (C), nitrogen at a pressure of about 1.42 kg/cm² absolute wasintroduced into the spray nozzle and the excess pressure applied to thestorage flask was 0.22 to 0.25 kg/cm². The spray nozzle was located atthe bottom of the spray drying apparatus and the hot nitrogen wasintroduced into the top of the spray drying appparatus so that thespraying was in an upward direction against a counter-current of hotnitrogen.

In stage (D), 30 grammes of the spray-dried product from stage (C) wereused and 300 cm³ of titanium tetrachloride for each treatment withtitanium tetrachloride.

In stage (E), washing was effected using 350 cm³ of the aliphatichydrocarbon for each wash. The residue was not allowed to cool after thefirst hot wash, the second hot was was effected directly after the firsthot wash and the residue was allowed to cool overnight after the secondhot wash. The cold washes were carried out on the cold residue of thesecond hot wash. The residue was diluted to a final volume of 300 cm³using the aliphatic hydrocarbon.

EXAMPLE 6

The remaining portion of the milled suspension obtained in stage (B) ofExample 5 was used. To this remaining portion was added a 10%weight/volume situation in toluene of polymethylmethacrylate (MH 254grade--available from Imperial Chemical Industries PLC). Thepolymethylmethacrylate solution was added to provide 2.0% by weight ofpolymethylmethacrylate relative to the milled magnesium chloride-ethylbenzoate. This suspension was diluted with toluene to give a finalsuspension having a 25% by weight solid content.

The suspension obtained was then spray-dried, treated with titaniumtetrachloride, washed and diluted as in stages (C), (D) and (E) ofExample 5.

EXAMPLES 7 TO 13

Polymerisation was carried out in an 8 dm³ stainless steel autoclave.

3 dm³ of the aliphatic hydrocarbon were charged into the autoclave anddegassed at 70° C. for 15 minutes at a pressure of 50 millimeters ofmercury. Propylene was then admitted to the vessel in an amount to givea pressure of 1.1 kg/cm² absolute. The aliphatic hydrocarbon was stirredand stirring was continued throughout the following procedures. 20millimole of aluminium tri-isobutyl were added to the autoclave as a 25%by weight solution in the aliphatic hydrocarbon. 7 millimoles of methylp-methylbenzoate were then added to the autoclave as a solution in thealiphatic hydrocarbon. A quantity of a suspension of a spray-driedmagnesium chloride supported titanium halide composition obtained in oneof Examples 1 to 6 was then added.

The autoclave was maintained at 70° C. while propylene was passed intothe autoclave to achieve a pressure of 11.5 kg/cm² absolute. 10millimoles of hydrogen were then added. The pressure was maintained at11.5 kg/cm² absolute by feeding propylene. After 0.5 hour, and againafter one hour, further 10 millimole quantities of hydrogen were addedto the autoclave. After 2 hours, the propylene feed was terminated andthe autoclave was vented to atmospheric pressure. The polymer suspensionwas passed into a receptacle and the polymer was filtered off in air. Asample of the polymer was dried at 100° C. in a fluidised bed usingnitrogen as the fluidising gas.

Further details of the polymerisation conditions, and the properties ofthe products obtained, are given in Table One.

                  TABLE ONE                                                       ______________________________________                                        Ti Compn.                                                                                 Amount                             PD                             Ex   Type   (cm.sup.3)                                                                             MFI  FM   Ti   Al   Cl    (g/l)                          (a)  (b)    (c)      (d)  (e)  (f)  (f)  (f)   (h)                            ______________________________________                                         7*  1      0.058*   25.5 1.47 5    197  186   ND                              8   2      3        10.4 1.45 9    457  280   339                             9** 3      4        23.0 1.42 9    293  220   ND                             10   4      4         7.0 1.43 5    285  195   390                            11   5      4        17.7 1.60 ND   ND   ND    404                            12   5      4        23.1 1.51 ND   ND   ND    ND                             13   6      4        ND   1.56 ND   ND   ND    422                            ______________________________________                                         Notes to Table One                                                            (a) *In this polymerisation, the pressure was maintained at 10 kg/cm.sup.     absolute.                                                                     **In this polymerisation, the pressure was maintained at 12.2 kg/cm.sup.2     absolute.                                                                     (b) Type refers to the Example in which the production of the titanium        composition is described.                                                     (c) Amount is the volume of suspension added.                                 *Amount is the number of millimoles of titanium present in the added          solid.                                                                        (d) MFI is melt flow index measured by ASTM Test Method D 1238/70,            Condition N (190° C. and 10 kg).                                       (e) FM is the flexural modulus expressed in GN/m.sup.2. The flexural          modulus was measured using a cantilever beam apparatus as described in        Polymer Age, March 1970, pages 57 and 58. The deformation of a test strip     at 1% skin strain after 60 seconds at 23° C. and 50% relative          humidity was measured. The test strip, which had dimensions of                approximately 150 × 19 × 1.6 mm, was prepared in the followin     manner. 23 g of the polymer were mixed with 0.1% by weight of an              antioxidant (`Topanol` CA), and the mixture was added to a Brabender          Plasticiser, at 190° C., 30 rpm and under a load of 10 kg to           convert it to a crepe. The crepe was placed within a template, between        aluminium foil and pressed by means of an electric Tangye press at a          temperature of 250° C. The pressing was preheated for a period of      minutes, under just enough pressure to make the polymer flow across the       template, that is an applied force of about 1 tonne. After the preheat        period, the applied force was raised to 15 tonnes in 5 tonne increments,      degassing (that is releasing pressure) every 5 tonnes. After 2 minutes at     15 tonnes, the press was cooled by means of air and water for 10 minutes      or until room temperature was reached. The plaque obtained was then cut       into strips of dimensions 150 × 19 × 1.6 mm. Duplicate strips     of each polymer were placed into an annealing oven at 130° C. and      after 2 hours at this temperature the heat was switched off and the oven      cooled to ambient temperature at 15° C. per hour.                      (f) The titanium (Ti), aluminium (Al) and chlorine (Cl) residues from the     catalyst are given in parts per million by weight relative to the total       polymer product (polymer + catalyst residues) and were measured by Xray       fluorescence on compression moulded discs.                                    (h) PD is the packing density which is determined by introducing 10           grammes of the polymer powder into a 50 cm.sup.3 flatbottomed graduated       tube of 2 cm internal diameter. The polymer powder is compacted by            striking the base of the tube against a horizontal surface a total of 30      times. The volume occupated by the polymer powder was then determined.        Duplicate measurements are made.                                              ND means that this property was not determined for the polymer.          

Some of the polymer products were subjected to particle size analysis bysieving and the results are set out in Table Two.

                  TABLE TWO                                                       ______________________________________                                        Particle                                                                      size     % Weight retained                                                    (microns)                                                                              Example 8    Example 11                                                                              Example 13                                    ______________________________________                                        >850     1.8          8.1       4.8                                           850-500  9.6          28.3      21.6                                          500-425  4.7          9.9       9.2                                           425-300  13.5         20.7      21.7                                          300-212  11.9         11.1      14.1                                          212-125  15.6         10.0      13.7                                          125-75   20.2         6.2       8.4                                            <75     22.8         5.7       6.4                                           ______________________________________                                    

In Examples 14, 15, 17 and 19, the spray-drying of a magnesium chloridesupport in accordance with the present invention was incorporated intothe procedure of our copending patent application Ser. No. 444,364entitled "Composition, Production and Use", which includes a treatmentwith a non-metallic halide, such as thionyl chloride. In all of Examples14 to 20, a suspension of magnesium chloride in a hydrocarbon liquid wassubjected to mechanical action in accordance with the procedure of ourcopending application Ser. No. 405,983, of even date herewith, entitled"Spraying Solid".

EXAMPLE 14 (A) Milling magnesium chloride, thionyl chloride and ethylbenzoate

Milling was effected in a Siebtechnik SM6 Vibromill chamber as used instage (A) of Example 2.

180.5 grammes of essentially anhydrous magnesium chloride (BDH technicalgrade) and 6.6 cm³ of thionyl chloride were introduced into the millchamber. The mill chamber was then placed in the mill assembly, water atambient temperature was passed through the jacket of the mill chamber,and the mill assembly was vibrated at a frequency of 1500 oscillationsper minute and an amplitude of 2 mm. The vibration was continued for twohours whilst continuing to pass water at ambient temperature through thejacket of mill chamber. The mill chamber was cooled over a period of1.25 hours by passing a mixture of water and ethylene glycol at -12° C.through the jacket of the mill chamber whilst continuing to vibrate themill assembly. Vibration of the mill assembly was stopped, 45.5 cm³ ofethyl benzoate were introduced into the mill assembly, vibration wasrestarted and continued for 24 hours. The molar ratio of magnesiumchloride to ethyl benzoate in the mill chamber was about 6 to 1.

(B) Milling with toluene

After 24 hours, 400 cm³ of toluene were added to the mill chamber whilstcontinuing to vibrate the mill. Milling was continued in the presence ofthe added toluene at 0° C. for a further 30 minutes.

After 30 minutes, the mill was inverted, the inverted mill was vibratedand the mixture of the milled solid and toluene was collected undernitrogen. The mill chamber was washed out with a further 300 cm³ oftoluene, which was added to the suspension previously removed.

After standing for 65 hours, the milled mixture was still fluid but wasviscous. The mixture was stirred and 39 cm³ of a 10% weight/volumesolution of polystyrene (`Styron` 686/7--available from Dow ChemicalCompany) in toluene was added to provide 2.0% by weight of polystyrenerelative to the milled solid. This mixture had a solid content of 24% byweight.

(C) Spray drying milled solid/toluene mixture

All of dispersion obtained in stage (B) was spray-dried using the glasslaboratory scale spray-drying apparatus used in stage (C) of Example 1.

Spraying was effected under nitrogen by passing a stream of nitrogen,preheated to a temperature of 145° C., into the spray-drying apparatusat a rate of 190 dm³ /minute. Nitrogen at a pressure of about 0.4 kg/cm²gauge was introduced into the spray nozzle. The suspension obtained instage (B) was fed from the 2 dm³ three-necked glass flask to the spraynozzle by the application of an excess nitrogen pressure of 0.04 kg/cm²to this flask.

(D) Contacting with titanium tetrachloride

A sample (39 grammes) of the spray dried product from stage (C) wastransferred to a 800 cm³ jacketted glass vessel which was provided witha stirrer. 390 cm³ of titanium tetrachloride were added to the vessel,the stirrer was started and heating was applied to the jacket. Heatingwas continued until a temperature of 100° C. was attained. Thetemperature was maintained at 100° C., and stirring was continued, forthree hours. At the end of three hours, the stirrer was stopped and thesolid was allowed to settle whilst continuing to heat the contents ofthe vessel. 50 minutes after terminating the stirring, the supernatantliquid was siphoned off from the settled solid. The heating was switchedoff and the contents of the vessel allowed to cool by standingovernight.

(E) Washing

To the residue remaining from stage (D) were added 450 cm³ of thealiphatic hydrocarbon at ambient temperature. The mixture was stirredand heated up to a temperature of 100° C. Stirring at 100° C. wascontinued for an hour and then ceased. After a further 75 minutes, thesupernatant liquid was siphoned off from the settled solid whilst stillheating. The heating was switched off and 450 cm³ of the aliphatichydrocarbon at ambient temperature were added to the hot residue. Themixture was stirred without heating for 15 minutes, then the stirrer wasswitched off and the solid allowed to settle. After one hour, thesupernatant liquid was siphoned off from the settled solid. This washingprocedure was repeated twice more.

The cold residue remaining from the fourth washing step was diluted withthe aliphatic hydrocarbon to give a final volume of 390 cm³ and themixture was transferred to a storage vessel under nitrogen.

EXAMPLE 15 (A) Milling magnesium chloride and ethyl benzoate

A Siebtechnik SM50 Vibromill having a total volume of about 165 litersand containing 570 kg of steel balls of 25 mm diameter was purgedthoroughly with nitrogen to give a nitrogen atmosphere in the mill. 16kilogrammes of anhydrous magnesium chloride (as used in Example 1) wereintroduced into the mill which was cooled to 31 10° C. by passing amixture of water and ethylene glycol at about -20° C. through the jacketof the mill.

Once the desired temperature had been achieved, the mill was vibratedusing a frequency of 1500 oscillations per minute and an amplitude of 2mm, whilst continuing to pass the mixture of water and ethylene glycolat -20° C. through the jacket of the mill.

4 dm³ of ethyl benzoate was added to the vibrating mill over a period of2.25 hours, during which time the temperature rose to about 20° C.Milling was continued, whilst still cooling the mill, for a totalmilling time of 24 hours. The molar ratio of magnesium chloride to ethylbenzoate in the mill was about 6 to 1.

(B) Milling with toluene

Without removing the milled magnesium chloride-ethyl benzoate product ofstage (A), 25 dm³ of toluene and 4 dm³ of a 10% weight/volume solutionof polystyrene in toluene (as used in stage (B) of Example 14) wereadded to the vibrating mill. Milling was continued, whilst cooling, fora further 30 minutes and the magnesium chloride suspension produced wastransferred, under nitrogen, into a drum of capacity 100 dm³.

25 dm³ of toluene were added to the mill, milling was effected for 20minutes and the liquid, together with any residual magnesium chloride,was transferred to the drum.

(C) Spray drying milled solid/toluene mixture

The contents of the drum obtained as described in stage (B), where driedusing spray-drying apparatus essentially as described with reference toFIG. 2. The spray-drying vessel had a diameter of 2.2 m, a cylindricalheight of 1.95 m and a 60° cone.

The circulating gas was nitrogen which was pre-heated to about 140° C.before entering the spray-drying vessel. The rate of supply of nitrogenwas about 650 kg per hour.

The suspension was not pre-heated and hence was at ambient temperatureon being fed to the spray-drying vessel.

The rate of rotation of the atomizer disc was 18,000 rpm and the timeduring which the suspension was fed to the spray-drying vessel was 20minutes.

(D) Contacting with thionyl chloride

A sample (16 grammes) of the spray dried product from stage (C) wastransferred to a 800 cm³ jacketted glass vessel which was provided witha stirrer. 160 cm³ of the aliphatic hydrocarbon and 0.4 cm³ of thionylchloride were added to the vessel, the stirrer was started and heatingwas applied to the jacket. Heating was continued until a temperature of50° C. was attained. The temperature was maintained at 50° C., andstirring was continued, for one hour. At the end of one hour, thestirrer was stopped and the solid was allowed to settle whilstcontinuing to heat the contents of the vessel. Ten minutes afterterminating the stirring, the supernatant liquid was siphoned off fromthe settled solid.

(E) Contacting with titanium tetrachloride

To the hot residue from stage (D) were added 160 cm³ of titaniumtetrachloride. The stirrer was started and heating was applied to thejacket. Heating was continued until a temperature of 100° C. wasattained. The temperature was maintained at 100° C., and stirring wascontinued, for three hours. At the end of three hours, the stirrer wasstopped and the solid was allowed to settle whilst continuing to heatthe contents of the vessel. 40 minutes after terminating the stirring,the supernatant liquid was siphoned off from the settled solid. Theheating was switched off and the contents of the vessel allowed to coolby standing overnight.

The treatment with titanium tetrachloride was repeated with theexception that the solid was allowed to settle for 45 minutes before thesupernatant liquid was siphoned off and the residue was not allowed tocool.

(F) Washing

To the hot residue remaining from stage (E) were added 200 cm³ of thealiphatic hydrocarbon at ambient temperature. The mixture was stirredand heating was continued to raise the temperature to 100° C. Stirringat 100° C. was continued for an hour and then ceased. After a further 25minutes, the supernatant liquid was siphoned off from the settled solidwhilst still heating. The heating was switched off and 200 cm³ of thealiphatic hydrocarbon at ambient temperature were added to the hotresidue. The mixture was stirred without heating for 10 minutes, thenthe stirrer was switched off and the solid allowed to settle. After onehour, the supernatant liquid was siphoned off from the settled solid.This washing procedure was repeated twice more.

The cold residue remaining from the fourth washing step was diluted withthe aliphatic hydrocarbon to give a final volume of 160 cm³ and themixture was transferred to a storage vessel under nitrogen.

EXAMPLE 16

The spray dried product of stage (C) of Example 15 was used and wassubsequently treated in a similar manner to that described for stages(D) and (E) of Example 14. This material was not contacted with thionylchloride.

(D) Contacting with titanium tetrachloride

The procedure of stage (D) of Example 14 was repeated using 27 grammesof the spray dried product of stage (C) of Example 15 and 270 cm³ oftitanium tetrachloride. The solid was allowed to settle for 15 minutesand the supernatant liquid was siphoned off but the residue was notallowed to cool.

(E) Washing

The procedure was essentially as described in stage (E) of Example 14with the exception that the hot residue from stage (D) was used and 300cm³ of the aliphatic hydrocarbon were used for each wash. After thesecond wash, the solid was allowed to cool and settle for about 65hours.

After the fourth wash, the residue was diluted to a volume of 270 cm³.

EXAMPLE 17

A sample of the spray dried product of stage (C) of Example 15 wastreated as generally described in stages (D), (E) and (F) of Example 15,but on a larger scale.

(D) Contacting with thionyl chloride

This was effected in a vessel of 6 dm³ capacity. 500 grammes of thespray dried product of stage (C) of Example 15, 5 dm³ of the aliphatichydrocarbon and 13 cm³ of thionyl chloride were used. The supernatantliquid was siphoned off 80 minutes after terminating the stirring.

(E) Contacting with titanium tetrachloride

This was effected in the same vessel as stage (D), using 3 dm³ oftitanium tetrachloride for each contacting and maintaining thetemperature at 100° C. for two hours. After the first contacting thesolid was allowed to settle for one hour and after the second contactingthe settling time was 1.5 hours.

(F) Washing

To the hot residue from stage (E) were added 5.5 dm³ of the aliphatichydrocarbon and the mixture was allowed to stand, without heating, for18 hours. The mixture was then stirred and heated to 100° C., maintainedat 100° C. for one hour, allowed to settle for 10 minutes and thesupernatant liquid was siphoned off. Heating was stopped and the threesubsequent washes were effected using 5.5 dm³ of the aliphatichydrocarbon for each wash. The residue was finally diluted to a totalvolume of 4.5 dm³.

EXAMPLE 18

The procedure was similar to that of Example 17 with the exception thatstages (D), (E) and (F) were effected using smaller quantities ofreagents and omitting thionyl chloride in stage (D).

(D) Contacting with the aliphatic hydrocarbon

200 grammes of the spray dried product of stage (C) of Example 15 and 2dm³ of the aliphatic hydrocarbon were used. The supernatant liquid wassiphoned off 35 minutes after terminating the stirring.

(E) Contacting with titanium tetrachloride

1.5 dm³ of titanium tetrachloride were used for the first contacting,and the solid was allowed to settle for 1.75 hours. Two dm³ of titaniumtetrachloride were added to the residue and the mixture was allowed tostand, without heating, for 18 hours. The mixture was stirred, heated to100° C., maintained at 100° C. for three hours and allowed to settle forone hour 20 minutes.

(F) Washing

Two dm³ of the aliphatic hydrocarbon were used for each wash. Thealiphatic hydrocarbon was added to the hot residue from stage (E) andthe temperature was raised to 100° C. After an hour at 100° C., thesolid was allowed to settle for 40 minutes. The subsequent three washeswere effected without heating and the residue was diluted to a totalvolume of 2 dm³.

EXAMPLE 19

The procedure was similar to that of Example 17 with the exception thatstages (D), (E) and (F) were effected using smaller quantities ofreagents and only one contacting step in stage (E).

(D) Contacting with thionyl chloride

200 grammes of the spray dried product of Example 15, 2 dm³ of thealiphatic hydrocarbon and 5.2 cm³ of thionyl chloride were used.

(E) Contacting with titanium tetrachloride

Two dm³ of titanium tetrachloride were used for a single contacting at100° C. for three hours.

(F) Washing

Washing was effected directly after the titanium tetrachloridecontacting, using 2 dm³ of the aliphatic hydrocarbon for each wash.

EXAMPLE 20

The procedure was as described for Example 19 with the exception thatstage (D) was omitted.

EXAMPLES 21 TO 28

Polymerisation was carried out in an 8 dm³ stainless steel autoclave ina manner generally as described for Examples 7 to 13 with the followingvariations. 40 cm³ of a solution in the aliphatic hydrocarbon containing20 millimole of aluminium triisobutyl were added to the autoclavefollowed by 40 cm³ of a solution in the aliphatic hydrocarbon containing7 millimoles of methyl p-methylbenzoate. 4 cm³ of a suspension of atitanium halide composition, obtained in one of Examples 14 to 20 werethen added as a suspension. Some Properties of the polymers obtained aregiven in Table Three.

                  TABLE THREE                                                     ______________________________________                                        Example                                                                              Ti       Polymer Properties                                            or     Compn                                  PD                              Comp   Type     MFI    FM     Ti  Al     Cl   (g/l)                           Example                                                                              (b)      (d)    (e)    (f) (f)    (f)  (h)                             ______________________________________                                        21     14       21.0   1.50   7   152    196  421                             22     15       37.3   1.53   6   152    210  408                             23     16       ND     1.40   7   155    ND   408                             24     17       31.5   1.42   8   134    177  408                             25     17       ND     1.48   6    99    195  413                             26     19       25.9   1.52   6   171    205  417                             27     18       47.7   1.52   9   171    193  417                             28     20       42.9   1.50   7   159    213  404                             ______________________________________                                         Notes to Table Three                                                          (b), (d), (e), (f) and (h) are all as defined in Notes to Table One.     

For each polymer, a sample of the filtered polymer was washed with 60-80petroleum ether and dried in a vacuum oven for 4 hours at a pressure of50 mm of mercury and a temperature of 60° C. The dried polymer wassubjected to particle size analysis by sieving and the results are setout in Table Four.

                  TABLE FOUR                                                      ______________________________________                                        Particle                                                                             % Weight Retained                                                      size   Ex     Ex     Ex    Ex   Ex   Ex    Ex   Ex                            (microns)                                                                            21     22     23    24   25   26    27   28                            ______________________________________                                        >850   2.9    1.6    0.5   2.5  1.2  1.2   0.9  0.8                           850-500                                                                              17.9   28.2   18.6  39.5 33.9 30.9  21.6 22.5                          500-425                                                                              7.1    13.1   12.3  16.3 16.5 16.2  12.6 12.7                          425-300                                                                              15.7   24.4   24.8  28.5 29.1 27.6  23.1 25.1                          300-212                                                                              9.9    13.0   14.0  9.4  13.2 13.4  12.7 13.5                          212-125                                                                              11.4   11.1   13.5  2.9  4.9  8.2   12.1 12.5                          125-75 11.9   5.4    9.9   0.8  1.0  2.1   8.0  7.5                            <75   23.2   3.3    7.5   0.1  0.3  0.4   9.0  5.5                           ______________________________________                                    

I claim:
 1. A process for the production of a supported transition metalcomposition wherein a solid support material which is a metal halide issuspended in a liquid medium which is a liquid hydrocarbon or a liquidhalohydrocarbon, the suspension is spray-dried, the spray-dried supportmaterial is collected and the collected spray-dried support material iscontacted with at least one compound of a transition metal of Group IVA,VA, or VIA of the Periodic Table.
 2. The process of claim 1 wherein thesolid support material is a magnesium halide.
 3. The process of claim 2wherein the metal halide which is the solid support material ismagnesium chloride which has been contacted with an ester of acarboxylic acid containing an aromatic group.
 4. The process of claim 1wherein the metal halide which is the solid support material issuspended in the liquid medium in an amount of at least one cm³ up to 30cm³ of the liquid medium for each gramme of the solid support material.5. The process of claim 1 wherein the suspension is spray-dried bypassing the suspension through an atomizer to form a spray of droplets,contacting the droplets with a stream of a gas which is essentiallyoxygen- and water vapour-free and is at a temperature of at least 80°C., evaporating liquid medium from the droplets and collecting aseparated solid product.
 6. The process of claim 1 wherein thesuspension which is spray-dried also contains an attrition inhibitorwhich renders the spray-dried solid more resistant to attrition.
 7. Theprocess of claim 6 wherein the suspension contains the attritioninhibitor in an amount of from 0.5% up to 10% by weight of the attritioninhibitor relative to the solid support material present in thesuspension.
 8. The process of claim 1 wherein, after spray-drying, thecollected spray-dried solid support material is subjected to at leastone contacting step with titanium tetrachloride.
 9. A process for theproduction of a polymerisation catalyst which comprises(1) forming atransition metal composition by the process of claim 1; and mixing theproduct obtained with (2) an organic compound of aluminium or of a metalof Group IIA of the Periodic Table or a complex of an organic compoundof a metal of Group IA or Group IIA of the Periodic Table together withan organic aluminium compound.
 10. The process of claim 2 wherein themetal halide which is the solid support is essentially anhydrousmagnesium chloride.
 11. The process of claim 6 wherein the attritioninhibitor is present as a solution in the liquid medium.